The objective of the proposed research is to examine certain aspects of glutaric acidemia (glutaryl-CoA dehydrogenase deficiency) and glutaric acidemia type II (multiple acyl-CoA dehydrogenase (deficiency), two recently described human inborn errors of metabolism, with the hope that the results will permit easier in-utero diagnosis as well as better understanding of their causes and pathogenesis. Specifically, our aims are (a) to devise an assay for disturbances of glutaryl-CoA metabolism in cultured fibroblasts that will be simple and sensitive enough to permit intrauterine diagnosis of fetuses with glutaric acidemia and glutaric acidemia type II, and to detect complementation between different cell lines with the same disorder, (b) to purify glutaryl-CoA dehydrogenase, to a degree sufficient to examine its properties, to prepare immune serum and monoclonal antibodies directed against it, and to use these antibodies to examine genetic heterogeneity in glutaric acidemia, and (c) to examine electron transport, electron transfer flavoprotein (ETF) and ETF dehydrogenase in mitochondria from normal and glutaric acidemia type II (GA2) cells, hoping to define the defect in GA2. 2,4-(14C) glutaric acid will be synthesized and whole cells assayed for disturbances in glutaryl-CoA oxidation by examining the incorporation of radiolabel from 14C-glutarate into protein; if present, complementation between different cell lines. Purification of GODH will be largely by affinity chromatography, and preparation of monoclonal antibodies against it offer the possibility of examining microheterogeneity of mutant alleles at the GCDH locus. To define the defect in GA2, we will examine electron transport from glutaryl-CoA to ETF and ETF dehydrogenase itself (by EPR). If indicated, we will prepare IgG against the normal protein that is defective in GA2, isolate the mutant protein from a GA2 liver in our possession on a Sepharose-IgG column, and then compare the mutant and normal proteins.